A local cop said he was forced to kill a mentally ill man to save his and other officer's lives.

On Monday in White Plains federal Court, Anthony Carelli, said he had, “no other option” but to shoot Kenneth Chamberlain Sr. because he believed the man was going to harm other officers.

The White Plains police officer also claimed that Chamberlain was provoking officers by saying they should shoot him, reports NBC.

The fatal shooting occurred on Nov. 19, 2011 in White Plains, when Chamberlin accidentally set off his LifeAid medical alert device. The former Marine was bipolar and dealt with a respiratory illness as well as arthritis.

Authorities say Chamberlin displayed a knife through a crack in his door and warned he was going to kill whoever entered first. After removing the door, police used a stun gun and bean bag weapon before the fatal shooting, NBC reports.

Police say once inside Chamberlin charged at one officer with a knife, prompting police to open fire.

Chamberlain’s family sued Carelli and the City of White Plains for $21 million. The family believes the fatal shooting was “systematic racism” by law enforcement.

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